While playing in a sandbox in Germany, an 8-year-old boy spotted a small silver object. A year later archaeologists examined the coin and concluded that he had stumbled on an ancient Roman coin that was minted 1,800 years ago.

The boy, identified only as Bjarne, was playing at an elementary school sandbox in Bremen when he spotted the silver item, the Bremen Senator for Culture said in an Aug. 11 news release. Not recognizing exactly what he’d found, Bjarne took the silver object home. Later, he brought the object to archaeologists — who identified it as a 1,800-year-old coin, Miami Herald reported.

According to Newsweek, the newly discovered coin was forged during the reign of Emperor Marcus Aurelius, who ruled over the Roman Empire from A.D. 161 to A.D. 180.

Photos show the front and back of the small coin. It has a pattern around the edge and a central figure. The coin is worn, making it difficult to see the details of the design.

It is not known how the coin ended up in Bremen, as the region was not part of the ancient Roman Empire. The coin could have come through trade, been carried by the river or brought as a souvenir, cultural officials said.